基于多功能罗丹宁化学的复杂高分子合成

合成能够达到生物大分子水平的复杂高分子是高分子化学的重要目标和研究前沿。多重大环结构的生物大分子广泛存在于生命体的进化过程中并担负着极为重要的生命功能，而人工合成复杂多环聚合物却非常困难。已有的闭环法和环加成法具有合成步骤繁琐、低效、产率低等不足，难以大量制备高分子量、环数目多、结构可调的多环聚合物。本项目提出新型环扩张法并开发包含五元环罗丹宁与醛基高效Knoevenagel 缩合和罗丹宁引发的环硫丙烷阴离子开环聚合的多功能罗丹宁化学。通过罗丹宁与醛基之间高效的Knoevenagel聚合制备各种结构可控的聚罗丹宁引发剂，再利用罗丹宁引发的开环聚合通过环扩张快速大量制备环尺寸和数目可控的线型、超支化、侧链悬挂大环的各种不同结构多环聚硫醚，并利用供体受体相互作用探索它们在发光材料等方面的应用。本项目的顺利实施可以为复杂多环聚合物提供全新的简便高效的合成途径，有望开辟多环拓扑聚合物应用的新领域。

The synthesis of complex macromolecules capable of reaching the level of biological macromolecules is an important goal and research front of polymer chemistry. Biomacromolecules with multiple ring structures widely exist in the evolution of living organisms and bear extremely important life functions. However, it is very difficult to synthesize complex artificial multicyclic polymers. The existing ring closure method and cycloaddition method have the disadvantages of complicated synthesis steps, low efficiency, low yield, etc., resulting in difficulty in large-scale preparation of multicyclic polymers with high molecular weights, large number of rings, and adjustable structures. This project proposes a new ring expansion method and develops a multifunctional rhodanine chemistry including highly efficient Knoevenagel condensation between five-membered ring rhodanine and aldehyde as well as rhodanine-initiated anionic ring-opening polymerization of thiiranes. Through the efficient Knoevenagel polymerization between rhodanine and aldehyde group, various poly(rhodanine) initiators with controllable structure can be prepared, and then the rhodanine-initiated ring-opening polymerization can be used to rapidly and extensively prepare linear, hyperbranched and pendant multicyclic polythioethers with controllable ring sizes and numbers through ring expansion method. Furthermore, we also use donor-acceptor interactions to explore the application of these multicyclic polymers in luminescent materials. The successful implementation of this project can provide a new, simple and efficient synthetic pathway for complex multicyclic polymers, and it is expected to open up new fields for the application of multicyclic topological polymers.